Ehresmann's lemma
In mathematics, Ehresmann's fibration theorem states that a smooth mapping
- f:M → N
where M and N are smooth manifolds, such that
- f is a submersion, and
- f is a proper map,
is a locally trivial fibration. This is a foundational result in differential topology, and exists in many further variants. It is due to Charles Ehresmann.
Reference
Ehresmann, C., Les connexions infinitésimales dans un espace fibré différentiable, Colloque de Topologie, Bruxelles (1950), 29-55.